Apparatus for Manufacturing Magnetic Recording Disk, and In-Line Type Substrate Processing Apparatus

ABSTRACT

An apparatus for manufacturing a magnetic recording disk includes a magnetic-film deposition chamber in which a magnetic film for a recording layer is deposited on a substrate; a lubricant-layer preparation chamber in which a lubricant layer is prepared on the substrate in vacuum; and a cleaning chamber in which the substrate is cleaned in vacuum after the magnetic-film deposition in the magnetic-film chamber and before the lubricant-layer preparation in the lubricant-layer chamber. The apparatus may further include a transfer system that transfers the substrate from the cleaning chamber to the lubricant-layer preparation chamber without exposing the substrate to the atmosphere.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of a patent application Ser. No.09/774,887 filed on Feb. 1, 2001.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

This invention relates to an apparatus for manufacturing magneticrecoding disks. Especially, this invention relates to an apparatusperforming a manufacturing method including a step of removingprotrusions on a substrate and a step of forming a lubricant film on thesubstrate.

The manufacture of a magnetic recording disk such as a hard disk isroughly divided into former steps and latter steps. The former stepsinclude deposition of an underlying film, deposition of a magnetic filmfor a recording layer, and deposition of an overcoat. The latter stepsinclude preparation of a lubricant layer and other required steps. Thelubricant layer is prepared considering contact of a magnetic head ontothe disk in read-out.

The preparation of the lubricant layer is carried out by a followingprocedure.

To begin with, a substrate is taken out to the atmosphere afterdeposition steps because thin-films such as the magnetic film for arecording layer are usually deposited in a vacuum chamber. Then,burnishing is carried out to remove contaminants adhering to thesubstrate and to remove protrusions formed on the substrate during thefilm depositions. The burnishing is a step of removing the protrusionsand the contaminants from the substrate by rubbing it with a tape-shapedpolishing member. The “contaminant” in this specification meansmaterials that may contaminate a substrate in general, which is a gas,ions, molecules, particles or other substances.

The lubricant layer is prepared after the burnishing. As lubricant,fluorine lubricant such as perfluoropolyether (PFPE) is used. Suchlubricant is diluted with solvent for improving uniformity. The dilutedlubricant is coated onto the substrate by such method as a dippingmethod where the substrate is dipped into the diluted lubricant, or aspin-coating method where the lubricant is dropped onto the substratewhen it is spun.

“Substrate” means a board that consists a magnetic recording disk inthis specification. “Surface of substrate” may mean a surface of a filmor layer when a film deposition or a layer preparation has already beencarried out onto the substrate.

Recent improvement of recording density in magnetic recording disks isremarkable. For example, in hard disks it is becoming 20 gigabit/inch2in the year 2000 and 40 gigabit/inch2 in the year 2001. One of factorsthat enable the improvement of the recording density is to reduce aspacing. FIG. 19 shows a view explaining the spacing.

In FIG. 19, the spacing in the case of hard disks is explained as anexample. As shown in FIG. 19, a hard disk has a structure where arecording layer 91 is prepared on a substrates 9, an overcoat 92 isdeposited on the recording layer 91, and a lubricant layer 93 isprepared on the overcoat 92. A magnetic head for writing and readinginformation is located at a position slightly apart from the surface ofthe hard disk. The spacing, which is designated by “S” in FIG. 19, meansdistance between a write-readout device element 900 of the magnetic headand the recording layer 91 of the hard disk. A distance between thewrite-readout device element 900 and the lubricant layer 93 is called a“flying height”, which is designated by “FH” in FIG. 19. It is importantto make the spacing S small in improving the recording density.

As the spacing S becomes smaller, demands to the manufacturing processhave been becoming severer by years. For reducing the spacing S, it isrequired not only to reduce the flying height FH, which is about 10 to20 nm in a typical hard disk drive (HDD) currently on sale in themarket, but also required to make a thickness of the overcoat 92 and athickness of the lubricant layer 93 thinner. As thickness of theovercoat 92 is made thinner, it is required to deposit a more compactand harder film as the overcoat 92. As the thickness of overcoat 92 ismade thinner, a demand for thickness uniformity of the lubricant layer93 becomes severer as well as a demand for enhancing an adhesionstrength of the lubricant layer 93 becomes severer.

With the above described points in the background, a method fordepositing the overcoat 9 has been shifting from a conventionalsputtering method to a chemical vapor deposition (CVD) method. Usually acarbon film is deposited as the overcoat 92. By the CVD method, it isenabled to deposit a carbon film called a “diamond-like carbon” (DLC)film. The DLC film is known as a hard, compact and stable carbon filmeven when its thickness is small. This is the reason why the method hasbeen shifting to the CVD method.

However, the contaminants of gases or ions may adhere to the overcoat 92under influence of residual gases when it is deposited by the CVDmethod. In addition, minute protrusions are easily formed on theovercoat 92 in the CVD method, resulting from abnormal film growth. Ifthe lubricant layer 93 is prepared over the overcoat 92 on which thecontaminants or the protrusions exist, there easily arise problems suchas the adhesion strength of the lubricant layer 93 may decrease, and thethickness of the lubricant layer 93 may lose uniformity.

The adhesion strength of the lubricant layer 93 is enhanced whenterminal groups of macromolecules composing the lubricant are bondedsufficiently with carbons in the overcoat 92. For making the adhesionstrength higher, it is preferable that the macromolecules are bondedwith carbons in the surface of the overcoat 92 at one of or bothterminal groups. On the other hand, it is desirable that a degree offreedom of the macromolecules is high at a portion adjacent to thesurface of the lubricant layer 93, on purpose of prevention thewrite-readout device element 900 of the magnetic head from chucking withthe disk. In short, both terminal groups are preferably not bonded nearthe surface of the lubricant layer.

A macromolecule bonded with a carbon at one of or both terminal groupsis hereinafter called a “bonded lub”. A macromolecule not bonded with acarbon at either of terminal groups is hereinafter called a “free lub”.A thickness ratio of the bonded lub layer against the whole lubricantlayer 93 is hereinafter called a “bonded ratio”. Though an optimumbonded ratio has been supposed about 20-30% so far, a demand foraccuracy of the bonded ratio tends to be severer as the lubricant layer93 is made thinner.

For obtaining the demanded bonded ratio, it has been attempted to carryout treatment for controlling the bonds of the terminal groups after thelubricant-layer preparation. In this treatment, thermal energy or lightenergy is applied to the lubricant layer 93, thereby controlling thebonds of the terminal groups. This treatment is hereinafter called“post-preparation treatment”.

However, when the overcoat 92 is exposed to the atmosphere after thedeposition, many contaminants of gases or ions in the atmosphere areadsorbed with the surface of the overcoat 92 because the surface hasbeen chemically activated. As a result, when the lubricant layer 93 isprepared, a contaminated layer may be formed between the lubricant layer93 and the overcoat 92. If the contaminated layer is formed, it maybecome difficult to obtain an accurate bonded ratio by thepost-preparation treatment. For preventing these problems, equipmentthat reduces the contaminants is required. Including such a point, thecurrent situation is that huge investment is inevitable for coordinatingmanufacture environment.

An object of the invention is to solve the described problems in themanufacturing process, which have been brought from the reduction of thespacing.

SUMMARY OF THE INVENTION

To accomplish this object, the invention presents a method and anapparatus for manufacturing a magnetic recording disk, where steps frommagnetic-film deposition to lubricant-layer preparation are carried outwithout breaking vacuum. The invention also presents a method and anapparatus for manufacturing a magnetic recording disk, where a substrateis cleaned prior to lubricant-layer preparation. The invention alsopresents a method and an apparatus for manufacturing a magneticrecording disk, where burnishing is carried out in vacuum aftermagnetic-film deposition. The invention also presents a method and anapparatus for manufacturing a magnetic recording disk, wherepost-preparation treatment to coordinate adhesive strength and surfacelubricity of a lubricant layer is carried out in vacuum. The inventionalso presents an in-line type substrate processing apparatus comprisinga plurality of vacuum chambers provided along each of a plurality ofcircumventive transfer paths, a connection transfer path connecting atleast two of the circumventive transfer paths, and a transfer systemthat transfers a substrate to be processed along the circumventivetransfer paths and the connection transfer path without exposing thesubstrate to the atmosphere.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic plane view of a magnetic recording diskmanufacturing apparatus of the first embodiment of the invention.

FIG. 2 shows a schematic front view of the first substrate holder 51 anda linear transfer mechanism in the apparatus shown in FIG. 1.

FIG. 3 shows a schematic side cross-sectional view of the firstsubstrate holder 51 and the linear transfer mechanism in the apparatusshown in FIG. 1

FIG. 4 shows a schematic side view of a direction-conversion mechanismprovided in a direction-changing chamber 17 shown in FIG. 1.

FIG. 5 shows a schematic plane view of a magnetic-film depositionchamber 14 shown in FIG. 1.

FIG. 6 shows a schematic plane view of an overcoat deposition chamber 15shown in FIG. 1.

FIG. 7 shows a schematic plane view the first cleaning chamber 22 shownin FIG. 1.

FIG. 8 shows a schematic plane view of the second cleaning chamber 22shown in FIG. 1.

FIG. 9 shows a schematic side view of a burnishing chamber 24 shown inFIG. 1.

FIG. 10 shows a schematic cross-sectional view of a rotation mechanism 8shown in FIG. 9.

FIG. 11 shows a front view explaining locations of contact blades 821shown in FIG. 10.

FIG. 12 shows s schematic side view of a drive mechanism 87 that drivesa pusher 247 shown in FIG. 9.

FIG. 13 shows a schematic side view of a lubricant-layer preparationchamber 25 shown in FIG. 1.

FIG. 14 shows a schematic side view of a post-preparation treatmentchamber 26 shown in FIG. 1.

FIG. 15 shows a main part of a magnetic recording disk manufacturingapparatus of the second embodiment of the invention.

FIG. 16 shows a main part of a magnetic recording disk manufacturingapparatus of the third embodiment of the invention.

FIG. 17 shows a main part of a magnetic recording disk manufacturingapparatus of the fourth embodiment of the invention.

FIG. 18 shows a main part of a magnetic recording disk manufacturingapparatus of the fifth embodiment of the invention.

FIG. 19 shows a view explaining a spacing.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of this invention are described as follows.

FIG. 1 shows a schematic plane view of a magnetic recording diskmanufacturing apparatus of the first embodiment of the invention. Thefirst point characterizing the first embodiment is that the former stepssuch as preparation of a recording layer and the latter steps such aspreparation of a lubricant layer can be carried out through only oneapparatus. The second point characterizing the first embodiment is thateach step from the recording layer preparation to the lubricant-layerpreparation can be carried out continuously in vacuum, i.e. withouttaking out a substrate 9 to the atmosphere.

In the concrete, the apparatus shown in FIG. 1 is an in-line typeapparatuses where a plurality of vacuum chambers 10-17, 20-29 isarranged along transfer paths 1,2 of the substrates 9. Each vacuumchamber 10-17, 20-29 is an airtight chamber pumped by a respective or acommon pumping system (not shown). In each boundary of the vacuumchambers 10-17, 20-29, a gate valve 4 is provided.

A plurality of the vacuum chambers 10-17, 20-29 is divided into thefirst group of the chambers 10-17 arranged along the first rectangulartransfer path (hereinafter, the first transfer path) 1, and the secondgroup of the chambers 20-29 arranged along the second rectangulartransfer path (hereinafter, the second transfer path) 2. The thirdtransfer path 3 connecting the first transfer path 1 and the secondtransfer path 2 is provided. A vacuum chamber 31 is also provided on thethird transfer path 3. This vacuum chamber 31 on third transfer path 3is connected airtightly with one vacuum chamber 16 of the first groupand one vacuum chamber 21 of the second group so that the substrate 9can be transferred from the first transfer path 1 to the second transferpath 2 without being taken out to the atmosphere.

In the vacuum chambers 10-17 of the first group, steps from theunderlying-film deposition to the overcoat deposition are carried out.In the vacuum chambers 20-29 of the second group, steps after theovercoat deposition to the lubricant-layer preparation are carried out.

A composition of a transfer system that transfers the substrate 9through the first, the second and the third transfer paths 1,2,3 isdescribed as follows. The transfer system is mainly composed of thefirst circulation means that circulates the first substrate holder 51holding the substrate 9 along the first transfer path 1, a loading robot61 that loads the substrate 9 to the substrate holder 51 on the firsttransfer path 1, the second circulation means that circulates the secondsubstrate holder 52 holding the substrate 9, an unloading robot 62 thatunloads the substrate 9 from the substrate holder 52 on the secondtransfer path 2, and a shifting robot 63 that unloads the substrate 9from the first substrate holder 51 and loads it to the second substrateholder 52.

The loading robot 61, the unloading robot 62 and the shifting robot 63are all the same robot basically, which comprises a multi-articulationarm for holding the substrate 9 at a tip of the arm. The first and thesecond substrate holders 51,52 are also the same composition. The firstand the second circulation means are basically the same composition aswell. As an example, the compositions of the first substrate holder 51and the first circulation means are described as follows.

The first circulation means is mainly composed of a linear movementmechanism that moves the first holders 51 linearly on the first transferpath 1, and a direction-conversion mechanism that converts a transferdirection of the first substrate holder 51. The compositions of thefirst substrate holder 51 and the linear movement mechanism aredescribed as follows using FIG. 2 and FIG. 3. FIG. 2 and FIG. 3 show thefirst substrate holder 51 and the linear movement mechanism employed inthe apparatus shown in FIG. 1. FIG. 2 shows a front view of them andFIG. 3 shows a side cross-sectional view of them.

The first substrate holder 51 is mainly composed of a main board 511 andpallets 512 fixed with the main board 511. Eight pallets 512 areprovided. Each group of four pallets 512 holds one substrate 9.Therefore, in this embodiment, the first substrate holder 51simultaneously holds two substrates 9. As shown in FIG. 2, the mainboard 511 has two cutouts. A shape of each cutout is nearly circle and alittle larger than the substrate 9. In each group of the pallets 512,two pallets 512 are fixed at one side edge of each cutout. The other twopallets 512 are fixed the other side edge of each cutout. The substrate9 is sandwiched between two couples of the pallets 512.

The main board 511 has another cutout elongated downward from both sidesof each nearly circular cutout. A vertically elongated spring band 514is provided in each cutout. A mount 515 is fixed at the top of eachspring band 514. As shown in FIG. 2, the mount 515 is a nearlytrapezoid-shaped plate. The pallet 512 is fixed on the top and thebottom of the mount 515 by screwing. The edge of each pallet 512 isV-shaped in which the edge of the substrate 9 is inlet.

Each robot 61, 62, 63 has a couple of levers 60 that curve a couple ofspring bands 514 against elasticity so that the pallets 512 shift awayfrom the nearly circular cutout. A loading operation of the substrate 9onto the first substrate holder 51 is described as follows. First, thelevers 60 curve the spring bands 514. In this state, the substrate 9 islocated at the center of the nearly circular cutout. Afterward, thelevers 60 are returned to the initial position so that the spring bands12 can restore the initial posture on elasticity. As a result, thesubstrate 9 is caught by the four pallets 512. By repeating the sameoperation so that the other substrate 9 is caught by the other fourpallets 512, two substrates 9 are held by the first substrate holder 51.The two substrates 9 are unloaded from the first substrate holder 51 byan operation quite reverse to this loading operation.

As shown in FIG. 2, many small magnets 513 are provided at the bottom ofthe first substrate holder 51. These magnets 513 are hereinafter called“holder magnets”. Each holder magnet 513 has magnetic poles on the topand the bottom. As shown in FIG. 2, the magnetic poles of the holdermagnets 513 are alternatively opposite in an array direction.

Beneath the first substrate holder 51, a magnetic-coupling roller 711 isprovided, interposing a partition wall 70. The magnetic-coupling roller711 is a cylinder, on which two spirally elongated magnets 712 areprovided as shown in FIG. 2. These magnets 712 are hereinafter called“roller magnets”. A surface pole of each roller magnet 712 is oppositeto each other. In short, the magnetic-coupling roller 711 has aso-called double-helix structure.

The magnetic-coupling roller 711 is provided at a position where theroller magnets 712 face to the holder magnet 513 through the partitionwall 70. The partition wall 70 is formed of material with a highmagnetic permeability. The holder magnets 513 and the roller magnets 712are magnetically coupled with each other. One side of the partition wall70 where the first substrate holder 51 is provided is a space kept at avacuum pressure. The other side of the partition wall 70 where themagnetic-coupling roller 711 is provided is a space of the atmosphericpressure. The magnetic-coupling roller 711 is provided along the firsttransfer path 1 shown in FIG. 1.

A multiplicity of main pulleys 714 that are rotated around horizontalaxes are provided along the first transfer path 1. As shown in FIG. 3,the first substrate holder 51 rides on the main pulleys 714. A couple ofsub-pulleys 715,715 are contacted with a lower margin of the firstsubstrate holder 51. The sub-pulleys 714,715 pinch the lower margin ofthe first substrate holder 51 to prevent fall of the first substrateholder 51. A multiplicity of the sub-pulleys 715, 715 are provided alongthe first transfer path 1 as well.

As shown in FIG. 3, a drive rod 716 is connected with themagnetic-coupling roller 711 through a bevel gear. A motor 717 isconnected with the drive rod 716 so that the magnetic-coupling roller711 can be rotated around its center axis by driving force transferredfrom the motor 717 through the drive rod 716.

When the magnetic-coupling roller 711 is rotated, the double-helixroller magnets 712 shown in FIG. 2 are also rotated. Situation that theroller magnets 712 are rotated is equivalent to situation that aplurality of aligned small magnets whose poles are alternately oppositesimultaneously move linearly along an aligning direction. Therefore, theholder magnets 513 magnetically coupled with the roller magnets 712 alsomove linearly as the roller magnets 712 are rotated, resulting in thatthe first substrate holder 51 moves linearly as a whole. During thisliner movement, the main pulleys 714 and the sub-pulleys 715,715 shownin FIG. 3 are driven to rotate following the movement.

In the composition shown in FIG. 1, the vacuum chambers provided atcorners of the first and the second transfer path 1, 2 are thedirection-conversion chambers 17, 29 comprising a direction-conversionmechanism that converts the transfer direction of the substrate 9 for 90degrees. Using FIG. 4, a composition of the direction-conversionmechanism provided in the direction-conversion chamber 17 is describedas an example FIG. 4 shows a schematic side view of thedirection-conversion mechanism provided in the direction-conversionchamber 17.

The direction-conversion mechanism shown in FIG. 4 is mainly composed ofa holder 721 holding the linear movement mechanism including themagnetic-coupling rollers of the same composition as described (notshown in FIG. 4), and a motor 722 for rotating the holder 721, therebyrotating the linear movement mechanism as a whole.

A drive rod 716 is connected with a shaft of a magnetic-coupling roller(not shown in FIG. 4) through a motion transfer mechanism such as abevel gear. Another bevel gear 723 is disposed at a rear end of thedrive rod 716 as shown in FIG. 4. A power transmission rod 724 posingvertically is connected with this bevel gear 723. A bevel gear 725engaging with the bevel gear 723 disposed at the rear end of drive rod716 is provided at the top of the power transmission rod 716. An outputshaft of a motor 717 is connected with a bottom end of the powertransmission rod 724.

On the other hand, the holder 721 composing the direction-conversionmechanism is a member having a shape of a column or a cylinder, whoseaxis is vertical. As shown in FIG. 4, the holder 721 has a through holelengthened vertically, through which the power transmission rod 724 isinserted. Bearings 725 are provided at a clearance between the innersurface of the through hole and the power transmission rod 724 so thatthe power transmission rod 724 is retained in the through hole whileallowing the rotation of the power transmission rod 724.

The described holder 721 is placed in a holder cover 726. The holdercover 726 has a nearly cylindrical shape and a larger radius than theholder 721. The holder cover 726, which supports the holder 721, isinstalled with a bottom wall 727 of the direction-conversion chambers17,29. The bottom wall 727 of the direction-conversion chambers 17,29has a circular opening with a size that suits an outer diameter of theholder cover 726. The holder cover 726 is fitted in this opening. Avacuum seal such as an O-ring is provided at an interface of the holdercover 726 and the bottom wall 727.

Four bearings 729 and a mechanical seal 728 are provided at a clearancebetween the holder cover 726 and the holder 721. The mechanical seal 728is interposed between the uppermost and next bearings 729. Themechanical seal 728 is to seal the clearance between the holder 721 andthe holder cover 726 while allowing a rotation of the holder 721. As themechanical seal 728, a seal mechanism using magnetic-fluid is preferablyemployed.

A pulley mount 730 is provided at the bottom of the holder 721. A holderpulley 731 is fixed at the bottom of the pulley mount 730. The holderpulley 731 is coaxial with the holder 721. A pulley 732 is provided at aposition at the same level as the holder pulleys 731. An output shaft ofa motor 722 is connected with the pulley 732. There is a belt 733stretching between the pulley 732 and the side pulleys 731 to connectthem. The pulley 731 and the pulley 732 are timing pulleys and the belt733 is a timing belt.

A frame 734 as shown in FIG. 4 is fixed on an upper surface of theholder 721. The frame 734 is to retain together the first substrateholder 51, the magnetic-coupling roller 711 and other members shown inFIG. 2. As shown in FIG. 4, several supports 735 are provided uprightlyon a lower part of the frame 734. The described main pulleys and thesub-pulleys are supported by the supports 735. A vacuum seal (not shown)is provided between the frame 734 and the holder 721 to prevent leak ofvacuum in the direction-conversion chamber 17 from the inside of theframe 734.

An operation of such a direction-conversion mechanism in thedirection-conversion chamber 17 is described as follows.

To begin with, when the motor 717 is operated, the rotation motion istransmitted to the magnetic-coupling roller (not shown in FIG. 4)through the power transmission rod 724 and the drive rod 716, therebyrotating the magnetic-coupling roller. As a result of this rotation, thefirst substrate holder 51 moves linearly.

When the first substrate holder 51 reaches a specific position in thedirection-conversion chamber 17, the motor 722 is operated. A drive ofthe motors 722 is transmitted to the pulley 731 via the pulley 732 bythe belt 733. As a result, the holder 721 is rotated, thereby rotatingthe linear transfer mechanism held by the holder 721 simultaneously.With this rotation, the first substrate holder 51 is also rotated. Whenthe rotation angle reaches 90 degrees, the operation of the motor 722 isstopped, thereby stopping the rotation of the first substrate holder 51.By this operation, the transfer direction of the first substrate holder51 is converted to a direction rotated by 90 degrees.

Afterwards, receiving a control signal, the linear transfer mechanism isdriven so that the first substrate holder 51 can be moved along thefirst transfer path 1 in the direction rotated by 90 degrees to a nextvacuum chamber. Therefore, the surface of the substrate 9 faces to theside of the transfer path 1, even after the substrate 9 turns a cornerof the rectangular first transfer path 1.

In the described composition of the direction-conversion mechanism, thecontrol of the rotation angle such as 90 degrees may be carried out bycontrol of the motor 722 or by a detector (not shown) detecting therotation angle of the holder 721.

Next are described details on the vacuum chambers of the first and thesecond groups.

First of all, the vacuum chambers of the first group are described. Thefirst group is composed of a load lock chamber 11 in which the substrate9 temporarily stays when it is transferred from the atmosphere, apre-heat chamber 12 to which the substrate 9 is transferred next fromthe load lock chamber 11, an underlying-film deposition chamber 13 towhich the substrate 9 is transferred next from the pre-heat chamber 12,a magnetic-film deposition chamber 14 to which the substrate 9 istransferred next to the underlying-film deposition chamber 13, theovercoat deposition chamber 15 to which the substrate 9 is transferrednext from the magnetic-film deposition chamber 14, the first transitionchamber 16 in which the substrate 9 temporarily stays when it istransferred to the second transfer path 2, the direction-conversionchambers 17, and an extra vacuum chamber 10.

The loading robot 61 is provided at the outside of the load lock chamber11. The loading robots 61 is a robot that takes out the substrate 9 froma cassette 611 placed at a load station in the atmosphere, and load itonto the first substrate holder 51.

The pre-heat chamber 12 is a chamber in which the substrate 9 is heatedto release gases existing on or in the substrate 9. The pre-heat chamber12 comprises a lamp heater in it so that the substrate 9 is heated to aspecific temperature.

In the underlying-film deposition chamber 13 and the magnetic-filmdeposition chamber 14, a specific thin-film is deposited by sputtering.As an example, components on the magnetic-film deposition chamber 14 aredescribed using FIG. 5. FIG. 5 shows a schematic plane view of themagnetic-film deposition chamber 14 shown in FIG. 1.

The magnetic-film deposition chamber 14 comprises a pumping system 141that discharge an air in the chamber, a gas-introduction system 142 thatintroduces a process gas into the inside of the chamber, a target 143whose surface to be sputtered is exposed to the inside space of themagnetic-film deposition chamber 14, a sputtering power supply 144 forapplying voltage to the target 143 to generate a sputtering discharge,and a magnet assembly 145 provided behind the target 143 for themagnetron sputtering.

While introducing the process gas such as argon into the magnetic-filmdeposition chamber 14 by the gas introduction system 142 and maintaininga specific vacuum pressure by the pumping system 141, the sputteringpower supply 144 is operated. As a result, the sputtering discharge isignited. Particles released from the target through the sputteringdischarge reach the substrate 9, thereby depositing a specific thin filmon the substrate 9.

The overcoat deposition chamber 15 comprises a plasma generation means150 so that plasma-enhanced chemical vapor deposition (PE-CVD) isenabled. FIG. 6 is a schematic plane view of the overcoat depositionchamber 15 shown in FIG. 1. The overcoat deposition chamber 15 comprisesa pumping system 151 for discharging an air in the chamber. The plasmageneration means 150 is mainly composed of a gas-introduction system 152that introduces a gas mixture of hydrocarbon such as CH₄ and hydrogeninto the chamber, and a HF power supply 153 for applying HF power to thegas mixture to form plasma P. Here, frequencies between LF (LowFrequency) and UHF (Ultra-High Frequency) are defined as RF (HighEfficiency). The hydrocarbon gas decomposes in the plasma P, therebydepositing a carbon thin-film on the substrate 9. A self-bias voltagemay be given to the substrate 9 by applying a HF voltage to thesubstrate 9 via the first substrate holder 51. The self-bias voltage isa voltage that has a negative direct current portion and is produced bya mutual reaction of the plasma P and the HF field.

In this embodiment, a couple of the underlying-film deposition chambers13 and a couple of the magnetic-film deposition chambers 14 areprovided, as shown in FIG. 1. The substrates 9 are transferred from oneunderlying-film deposition chamber 13, to the other underlying-filmdeposition chamber 13, to one magnetic-film deposition chamber 14, tothe other magnetic-film deposition chamber 14 in order. In other words,the underlying film is deposited in a form of a double layer. And, themagnetic film is deposited on the double-layered underlying film in aform of a double layer as well. There may be another structure where alayer made of the underlying film and the magnetic film is doubled.Showing examples of the films, a Cr film is deposited as the underlyingfilm, and a CoCrTa film is deposited as the magnetic film. As shown inFIG. 1, a couple of the overcoat deposition chambers 15 are provided. Inthe first overcoat deposition chamber 15, the overcoat is deposited athalf of required thickness, and in the second overcoat depositionchamber 1S the overcoat with the rest half thickness is deposited.

Next are described details on the vacuum chambers of the second group.

The chambers of the second group is composed of the second transitionchamber 21 in which the substrate 9 temporarily stays after thesubstrate 9 is transferred through the first transfer path 1 and thethird transfer path 3, the first cleaning chamber 22 in whichcontaminants are removed from the substrates 9 by a plasma ashingmethod, the second cleaning chamber 23 in which contaminants are removedfrom the substrates 9 by a gas blowing method, a burnishing chamber 24in which protrusions on the substrates 9 are removed, a lubricant-layerpreparation chamber 25 in which the lubricant layer is prepared on thesubstrates 9, the post-preparation treatment chamber 26 in which thetreatment is carried out after the lubricant-layer preparation, thecooling chamber 27, an extra chamber 20, an unload lock chamber 28 inwhich the substrate 9 temporarily stays when the substrate 9 istransferred to the atmosphere, and the direction-conversion chambers 29.

One of points that characterize this embodiment is the first cleaningchamber 22. Components on the first cleaning chamber 22 are describedusing FIG. 7. FIG. 7 shows a schematic plane view of the first cleaningchamber 22 shown in FIG. 1.

In the first cleaning chamber 22, the contaminants are ashed by oxygenplasma. The components on the first cleaning chamber 22 are almost thesame as on the overcoat deposition chamber 15 shown in FIG. 6, exceptthat a gas-introduction system 222 introduces an oxygen gas. Concretely,the first cleaning chamber 22 comprises a couple of HF electrodes 223located at both sides of the substrates 9 and a HF power source 224 thatapplies the HF voltage to the electrodes 223 to generate the plasma P.

The HF electrodes 223 are hollow and have a number of gas effusion holeson a surface facing to the substrates 9. The gas-introduction system 222introduces oxygen gas into the first cleaning chamber 22 through theinside of the HF electrode 223. The gas-introduction system 222 may mixa buffer gas or a gas for improving discharge characteristics with theoxygen gas.

Contaminants formed of carbon or hydrocarbon sometimes adhere to thesurface of the overcoat deposited on the substrates 9. Adhesion of thecontaminants is caused from factors as described next. The adhesion ofcarbon mainly results from suspended particles in the overcoatdeposition chamber 15. In the overcoat deposition chamber 15, thinfilms, i.e. carbon films, are deposited not only on the surfaces of thesubstrates 9 but also on exposed surfaces of members in the overcoatdeposition chamber 15 and a surface of the first substrate holder 51.These thin-films may be peeled off by internal stress or anotherfactors, when those grow to be thick films. The peeled thin filmproduces the suspended particles in the overcoat deposition chamber 15.If the particles adhere to the substrates 9, the wettability, i.e. adegree of contact, of the lubricant may deteriorate in thelubricant-layer preparation. Otherwise, abnormal film growth may takeplace to form minute protrusions on the substrates 9 in the overcoatdeposition.

The adhesion of hydrocarbon is mainly caused under influence of residualgases in the overcoat deposition chamber 15. Though the overcoat isdeposited utilizing decomposition of the hydrocarbon gas in the plasma,non-decomposed hydrocarbon gases still reside in the overcoat depositionchamber 15. These residual gases may adhere to the substrates 9. Whenadhesion of the residual gases is accumulated, the residual gases maygrow to be molecules or particles of some size on the substrate 9. Ifsuch molecules or particles are produced on the surface of the substrate9, wettability of the lubricant may deteriorate, or characteristics ofthe lubricant layer may be affected.

When the substrate 9 on which such contaminants exist is exposed to theoxygen plasma, the carbon and hydrocarbon are rapidly oxidized, i.e.burnt, thereby becoming volatile substances such as carbon dioxide andwater. This oxidation is caused by species produced in the oxygen plasmasuch as oxygen ions, monoatomic oxygen molecules (O) that are active,and activated oxygen molecules (O2*). Those volatile substances arepumped out by the pumping system 221 of the first cleaning chamber 22.By carrying out such the ashing, it is enabled to suppress the problemsthat adhesion strength of the lubricant may decrease, and that amagnetic head may be obstructed by the minute protrusions on the surfaceof the magnetic recording disk.

On condition of the ashing, prudent examination is required. This isbecause excessive ashing may lead to eroding the surface of theovercoat, TABLE 1 shows a preferred example of conditions of the ashingon a substrate of 3.5-inch size.

TABLE 1 Preferred Ashing Condition Condition Preferred range or valuePressure in the chamber 22 1-2 (Pa) Flow rate of oxygen gas 100 (SCCM)HF power 50 (W) Frequency 13.56 (MHz)

In TABLE 1, “SCCM” means a gas flow rate converted at 0° C. and 1 atm,standing for “Standard Cubic Centimeter per Minute”. When the ashing iscarried out on the above condition, the contaminants can be removedwithin 0.3-2.0 seconds, while preventing the problem of the overcoaterosion. If the ashing is carried out with HF power over 50 W, or if theashing is carried out over 2.0 seconds, the overcoat might be eroded.Therefore, it is preferable that the ashing is carried out with HF powerof SOW or less and for 2.0 seconds or less.

Next are described components on the second cleaning chamber 23. FIG. 8shows a schematic plane view of the second cleaning chamber 23 shown inFIG. 1.

The second cleaning chamber 23 comprises a pumping system 231 thatdischarges an air in the chamber, and a couple of gas introduction tubes233 having a nozzle 232 that eject a gas toward the substrates 9. Eachnozzle 232 is a circular disk and parallel to the substrates 9. Eachnozzle 232 has a diameter little larger than that of the substrate 9.Many gas ejection holes are provided on each nozzle 232 with an equalinterval.

The gas is ejected from each nozzle 232 onto of the substrates 9 so thatthe contaminants adhering on the substrates 9 can be blown away. Apressure in the second cleaning chamber 23 is about 1×10⁻⁴-1×10⁻⁵ Pa,and an ejection pressure of the gas at the substrates 9 is about 100 Pa.For this gas, an inert gas such as argon or nitrogen is adopted. Afilter that removes the contaminants is preferably provided on a gasintroduction line (not shown) connected with the gas introduction tube233.

It may be possible to carry out the described gas-blow cleaning at theatmosphere. However, the gas-blow cleaning in the atmosphere has higherprobability that the contaminants still remain after the cleaning thanthe cleaning in vacuum, because cleanliness of ambience is worse.

It can be adopted to clean the substrate 9 by extra-fine fibers insteadof the cleaning by the plasma or the gas blow. Specifically, thesubstrate 9 is rubbed with a fabric made of extra-fine fibers of about0.06 denier. This fabric is similar to one that is on sale as a glasswiper.

Next is described about the burnishing chamber 24.

FIG. 9 shows a schematic side view of the burnishing chamber 24 shown inFIG. 1. As shown in FIG. 9, the burnishing chamber 24 comprises apumping system 241 that discharges an air in the chamber, a rotationmechanisms 8 that holds and rotates the substrate 9 around a rotationaxis corresponding to the center of the substrate 9, and a burnishingtape 242 that is pressed on the substrate 9 being rotated by therotation mechanism 8.

A detail of the rotation mechanisms 8 is described using FIG. 10. FIG.10 shows a schematic cross-sectional view of the rotation mechanism 8shown in FIG. 9. As shown in FIG. 10, the rotation mechanism 8 is mainlycomposed of a back-and-fore drive shaft 81 elongated horizontally, acylindrical rotation drive shaft 82 provided coaxially with theback-and-fore drive shaft 81, the first back-and-fore drive source 83that drives the back-and-fore drive shaft 81, a rotation drive source 84that rotates the rotation shaft 82, and the second back-and-fore drivesource 85 which moves backward or forward the back-and-fore drive shaft81 and the rotation drive shaft 82 together.

At an end of the back-and-fore drive shaft 81, a drive head 86 isprovided. The drive head 86 is formed of a disk portion 861 that isslightly smaller than a center opening of the substrate 9, and a taperportion 862 with a shape of circular cone coaxial with the back-and-foredrive shaft 81.

Contact blades 821 are provided at an end of the rotation drive shaft82. The contact blades 821 are members that contact an inner edge of thecenter opening of the substrate 9, when the substrate 9 is held by therotation mechanism 8. FIG. 11 shows a front view explaining locations ofthe contact blades 821 shown in FIG. 10. As shown in FIG. 11, threecontact blades 821 are provided at every 120 degrees on a circumferencecoaxial with the back-and-fore drive shaft 81. As shown in FIG. 10, across-sectional shape of each contact blade 821 is like a curved concaveor a “V”-shape.

As shown in FIG. 10, driven blades 822 contacting a tapered surface ofthe taper portion 862 are provided. Connection plates 824 are provided.The connection plates 824 connect each driven blade 822 and each contactblade 821 respectively. Projections are provided on an end of therotation shaft 82. Spring members 823 such as coil springs connectingeach protrusion and each driven blade 22 are provided. Each driven blade822 is fixed with each projection through each spring member 823. Thecontact blades 821 are located outside the projections. The contactblades 821 can slide on the end of the rotation shaft 82.

The back-and-fore drive shaft 81 is connected with the firstback-and-fore drive source 83 through a joint mechanism 811 capable ofdisconnection. The first back-and-fore drive source 83 is a linearmotion source that is a combination of a servomotor and a precise screw,or a linear actuator such as an air cylinder. The rotation drive source84 is a motor connected with the outer surface of the rotation driveshaft 82 through gears. The second drive source 85 moves the frame 851backward or forward, on which the back-and-fore drive shaft 81, therotation driving shaft 82, the first back-and-fore drive source 83 aremounted, thereby moving them simultaneously as a whole. The rotationdrive shaft 82 penetrates airtightly a wall of the burnishing chamber 24with a vacuum seal such as a mechanical seal.

A lever (not shown) linked to the described rotation mechanism 8 isprovided in the burnishing chamber 23. This lever has the same functionas the described lever 60 provided in each robot 61, 62, 63.

On the other hand, a storing roller 243 for storing the burnishing tape242 is provided in the burnishing chamber 24. The burnishing tape 242 isrolled up around the storing roller 243 in advance. The burnishing tape242 is used for the burnishing, being rolled out from the storing roller243. A retrieval roller 244 that retrieves a used portion of theburnishing tape 242 is provided in the burnishing chamber 24. Theretrieval roller 244 is rotated by a vacuum motor (a motor operatable ina vacuum environment) 245 to retrieve the used portion of the burnishingtape 242. During this rotation for the retrieval, the storing roller 243is forced to rotate, thereby drawing out a virgin portion of theburnishing tape 242.

A pressure member 247 that presses the burnishing tape 242 against thesubstrate 9 is provided. A drive mechanism 87 is also provided in thepressure member 247. FIG. 12 shows a schematic side view of the drivemechanism 87 that drives the pressure member 247 shown in FIG. 9.

As shown in FIG. 12, the drive mechanism is mainly composed of a driveshaft 871, a torque motor 872 that drives the drive shaft 871, a lineardrive source 873 for moving backward or forward the drive shaft 871 andthe torque motor 872 together. The pressure member 247 is fixed at anend of the drive shaft 871. The torque motor moves the drive shaft 871forward so that the pressure member 247 is pressed against the substrate9.

A precise screw, or a ball thread, 874 is jointed with an output shaftof the torque motor 872. A rear portion of the drive shaft 871 ishollow. An inner surface of this portion is screwed, with which theprecise screw 874 is engaged. A rotation of the drive shaft 871 isrestrained by a restraint member (not shown). As the linear drive source873, a combination of a motor and a precise screw, or an air cylinder isadopted. The drive shaft 871 airtightly penetrates a wall of theburnishing chamber 24 with a vacuum seal such as a mechanical seal. Asunderstood from FIG. 9, the burnishing tape 242, the storing roller 243,the retrieval roller 244, the vacuum motor 245, the pressure member 247and the drive mechanism are provided at both sides of a location of thesubstrate 9, respectively.

A width of a pressing area on the pressure member 247 is nearly the sameas a difference between a radius of the center opening and a radius ofthe substrate 9. The width of the pressing area may be shortened, if thesubstrate 9 moves along a radius direction relative to the burnishingtape 243 and the pressure member 247 while the substrate 9 is rotated.

An operation of the burnishing chamber 24 is described as follows.

The burnishing chamber 24 is pumped by the pumping system 241 inadvance. The second back-and-fore drive source 85 moves theback-and-fore drive shaft 81 and the rotation shaft 82 to a standbyposition in advance. In a state that a pressure in the burnishingchamber 24 is maintained at a specific vacuum pressure, the secondsubstrate holder 52 holding the substrates 9 is moved into theburnishing chamber 24. The second substrate holder 52 is stopped at aposition where the center of one of the substrates 9 corresponds to thecenter axis of the back-and-fore drive shaft 81 shown in FIG. 9 and FIG.10.

Next, the second back-and-fore drive source 85 is operated to move theback-and-fore drive shaft 81 and the rotation drive shaft 82 forwardsimultaneously. The back-and-fore drive shaft 81 and the rotation driveshaft 82 are stopped at a position where the drive head 86 is projectedthrough the opening of the substrate 9 and the contact blades 821 arelocated at the same vertical plane as the substrate 9, as shown in FIG.10.

In this state, the first back-and-fore drive source 83 is operated tomove the back-and-fore drive shaft 81 backward. As the back-and-foredrive shaft 81 is moved backward, the driven blades 822 contacting thetapered surface of the taper portion 862 shift outward againstelasticity of the spring member 823. Concurrently, each contact blade821 also shifts outward, thereby contacting the inner edge of the centeropening of the substrate 9. The first back-and-fore drive source 83applies adequate force that works so as to move the back-and-fore driveshaft 81 backward. Therefore, each contact blade 821 is pressed onto theinner edge of the center opening of the substrate 9 adequately. Withthis operation, the substrate 9 is held by the rotation mechanism 8.

In this state, the lever (not shown in FIG. 9) is driven to expand eachof the spring bands (not shown in FIG. 9) outwardly. As a result, thesubstrate 9 is held only by the rotation mechanism 8.

Next, the rotation drive source 84 of the rotation mechanism 8 isoperated to rotate the back-and-fore drive shaft 81 and the rotationdrive shaft 82 together. With the rotations of the back-and-fore driveshaft 81 and the rotation drive shaft 82, the substrate 9 held by thecontact blades 821 is also rotated. During this rotation, the jointmechanism 811 disconnects the back-and-fore drive shaft 81 from thefirst back-and-fore drive source 83.

While the substrate 9 is rotated, the drive mechanism 87 at both sidesof the substrates is operated. The pressure members 247 at both sidesare moved to a specific fore position by the linear drive source 873.This fore position is slightly back is from a position at which thepressure member 247 just presses the burnishing tape against thesubstrate 9. Next, the torque motor 872 is operated to move the pressuremember 247 slightly forward. As a result, the pressure member 247presses the burnishing tape 242 against the substrate 9. A generatedtorque is adjusted to control a press pressure of the burnishing tape242 at a specific value.

The substrate 9 is rubbed with the pressed burnishing tape 242,resulting in that the protrusions on the substrate 9 are removed. Inaddition to the protrusion removal, the contaminations are sometimesremoved if those have adhered to the substrate 9. The burnishing tape242 is, for example, a tape made of polyethlene-terephthalate orpolyamide, on which many abrasive grains such as alumina grains orsilicon carbide gains are fixed. A rotation speed of the substrate 9 maybe 100-4000 rpm.

Prudent examination is required for determining a pressing force of thepressure member 247. When the burnishing by the burnishing tape 242 iscarried out in vacuum, a friction force between the burnishing tape 242and the substrate 9 is higher than that in the atmosphere. Therefore, ifthe burnishing tape is pressed with the same force as in the case of theburnishing in the atmosphere, the substrate 9 is scraped excessively. Asa result, not only protrusion can be removed, but also thickness of theovercoat might be made thinner. For example, in the case of theburnishing at about 1.0×10⁻²-100 Pa, a pressure force is preferably9.8-588 mN.

There may be a case that the burnishing is carried out without movingthe substrate 9 but with moving the burnishing tape 242, i.e. withretrieving the burnishing tape, while the burnishing tape 242 is pressedagainst the substrate 9. In this case, the pressure member 247 ismodified into a member that corresponds with a following roller.

After carrying out the described burnishing on the whole surface of thesubstrate 9, the drive mechanism 8 moves the pressure member 247 to aspecific back position, and the operation of the rotation drive source84 is stopped. Next, the lever releases the spring bands to make thesecond substrate holder 52 hold the substrate 9 by the pallets again.After the first back-and-fore drive source 83 and the back-and-foredrive shaft 81 are jointed by the joint mechanism 811 again, the firstback-and-fore drive source 83 moves the back-and-fore drive shaft 81forward by a specific distance. As a result, the contact blades 821 aremoved inside by elasticity of the spring member 823, and the rotationmechanism 8 releases the substrate 9. Then, the second back-and-foredrive source 85 moves the back-and-fore drive shaft 81 and the rotationdrive shaft 82 backward together to the initial stand-by position.

Next, the second substrate holder 52 is moved to a position where thecenter of the other substrate 9 is just on an axis of the back-and-foredrive shaft 81. Then, the burnishing is carried out on the othersubstrate 9 as well by repeating the same operation as described. Asshown in FIG. 1, a couple of the burnishing chambers 24 are providedinterposing the lubricant-layer preparation chamber 25. Therefore, theburnishing is carried out before and after the lubricant-layerpreparation.

Next is described about the lubricant-layer preparation chamber 25.

FIG. 13 shows a schematic side view of the lubricant-layer preparationchamber 25 shown in FIG. 1. The lubricant-layer preparation chamber 25is a chamber in which the lubricant layer is prepared on the substrate 9in vacuum. The lubricant layer is prepared by the vacuum vapordeposition method in the lubricant-layer preparation chamber 25.

As shown in FIG. 13, the lubricant-layer preparation chamber 25comprises a pumping system that discharges an air in the chamber, acouple of pots 252 in which lubricant is stored, a heater 253 forevaporating the lubricant in each pot 252, and a rotation mechanism 8for rotating the substrate 9 during the deposition.

The lubricant is stored in the pots 252 without diluting with anysolvent. The heater 253 is a kind of resistance heaters. Other than theresistance heaters, an electron-beam irradiation heater or an HFinduction heater may be employed as the heater 253. A shutter isprovided over each pot 252 if necessary.

The rotation mechanism 8 may be the same as one provided in theburnishing chamber 24 shown in FIG. 9. In this embodiment, a couple ofthe rotation mechanisms 8 are provided so that two substrates 9 can berotated simultaneously.

An operation of the lubricant-layer preparation chamber 25 shown in FIG.13 is described as follows.

The lubricant-layer preparation chamber 25 is pumped by the pumpingsystem 251 in advance. In a state that a pressure in the burnishingchamber 25 is maintained at a specific vacuum pressure, the secondsubstrate holder 52 holding the substrates 9 is moved into thelubricant-layer preparation chamber 25 and is stopped. Each rotationmechanism 8 holds and rotates each substrate 9, respectively.Simultaneously, each heater 253 heats the lubricant in each pot 252. Thelubricant is evaporated by heating, thereby depositing a lubricant filmas the lubricant layer on each substrate 9. The lubricant layer isprepared on two substrates 9 simultaneously. A principal component ofthe lubricant may be PEPE. A molecular weight of the lubricant may be2000-4000. As commercially available lubricant of this kind, there areZDOL200 and ZDOL4000 (production names) of AUSMONT Corporation.

A heating temperature by the heater may be 50-310° C. A pressure in thelubricant-layer preparation chamber 25 may be about 1.0×10⁻²-10 Pa. Whenthe deposition is carried out under such conditions, the lubricant filmof 1-2 nm in thickness is deposited within 3-5 seconds. A rotation speedis lower than that in the described burnishing. Specifically, it may beabout 5-500 rpm.

After carrying out the lubricant-layer preparation, the operations ofthe heater 253 and the rotation mechanisms 8 are stopped. The substrates9 are returned to the second substrate holder 52. After thelubricant-layer preparation chamber 25 is pumped again, the secondsubstrate holder 52 is moved to the next post-preparation treatmentchamber 26.

Next are described about the post-preparation treatment chamber 26 andthe cooling chamber 27. FIG. 14 shows a schematic side view of thepost-preparation treatment chamber as shown in FIG. 1.

The optimum bonded ratio is supposed 20-30% as described. In thisembodiment, a bonded ratio within this range is accomplished by heatingthe substrates 9 in the post-preparation treatment chamber 26, and byoptimizing a heating temperature and a heating time. Specifically, theabove bonded ratio is accomplished by maintaining a temperature of thesubstrate 9 at 30-150° C. for 3-5 seconds.

As shown in FIG. 14, an infrared (IR) lamp 261 is provided at both sidesof the substrate 9 held with the second substrate holder 52 in thepost-preparation treatment chamber 26. A pumping system 262 is providedin the post-preparation treatment chamber 26. The pumping system 262pumps the post-preparation treatment chamber 26 to maintain a pressureat 1×10⁻⁴-1×10⁻⁵ Pa during the post-preparation treatment. Although thevacuum is not an indispensable condition for the post-preparationtreatment because this is the step after the lubricant preparation, itis enabled to prevent the contaminants from being adsorbed on a hotsurface of the heated lubricant layer by carrying out thepost-preparation treatment in vacuum.

Instead of the heating, the post-preparation treatment may be carriedout by irradiation. For example, in a case that the lubricant is capableof photo polymerization, a degree of the polymerization of the lubricantcan be controlled by irradiating light such as ultraviolet ray. By thiscontrol, it is possible to adjust an adhesive strength and surfacelubricity of the lubricant layer. If this method is employed, anultraviolet (UV) lamp may be used instead of the IR lamp 261.

The cooling chamber 27 is one for cooling the substrate 9 after thetreatment so that the unloading robot 62 can easily handle the substrate9 in the unload lock chamber 28. In the cooling chamber 27, a coolinggas such as hydrogen or helium is blown on the substrate 9, therebycooling it down at about 100° C. or below. The cooling system disclosedin Japanese Patent Publication No. 11-203734 is preferably applied tothis cooling chamber 27. The unloading robot 62 provided in the unloadlock chamber 28 takes out the substrate 9 from the second substrateholder 52, and transfer it to an unloading cassette 621 placed in theatmosphere.

Next is described a whole operation of the apparatus of this embodimentas follows. The following is a description of a manufacturing methodaccording to an embodiment of the invention too.

Two of the substrates 9 are transferred from the loading cassette 611 inthe atmosphere to the load lock chamber 11 by the loading robot 61 pieceby piece, and are loaded on the first substrate holder 51. The firstsubstrate holder 51 is moved to the pre-heat chamber 12. The substrates9 are pre-heated in the pre-heat chamber 12. After the pre-heating, thefirst substrate holder 51 is moved to the underlying-film depositionchamber 13, the magnetic-film deposition chamber 14, and the overcoatdeposition chamber 15 in order, thereby accumulatively depositing theunderling film, the magnetic film and the overcoat on the substrates 9.

The substrates 9 are unloaded from the first substrate holder 51 by theshifting robot 63 in the first transition chamber 16, and are loaded onthe second substrate holder 52 on standby in the second transitionchamber 21. The first substrate holder 51 without the substrates 9 isreturned to the load lock chamber 11, in which next two substrates 9 areloaded.

On the other hand, the second substrate holder 52 holding the substrates9 is moved to the first cleaning chamber 22, the second cleaning chamber23, the burnishing chamber 24 and the lubricant-layer preparationchamber 25 in order, thereby preparing the lubricant layer on theovercoat. Consequently, the second substrate holder 52 is moved to thepost-preparation treatment chamber 26 and the cooling chamber in order,thereby carrying out the treatment and the cooling of the substrates 9.When the second substrate holder 52 reaches the unload lock chamber 28,the substrates 9 are unloaded from the second substrate holder 52 andtransferred out to the unloading cassette 621 at the atmosphere. Thesecond substrate holder 52 without the substrates 9 is moved to thesecond transition chamber 21 for holding next two substrates 9. Thesecond substrate holder 52 holding the next two substrates 9 iscirculated along the second transfer path 2. During this operation, ineach chamber 10-17, 20-29, the first substrate holder 51 or the secondsubstrate holder 52 is located. Each substrate holder 51,52 is moved tothe next chamber 10-17, 20-29 at every tact time.

The described apparatus of this embodiment has advantages as follows.

First of all, because it is possible to carry out the steps from theunderlying-film deposition to the lubricant-layer preparation with theonly one apparatus, costs such as an equipment cost for manufacture anda labor cost for operation are reduced. An unmanned operation ispossible while all the substrates 9 in the loading cassette 611 areprocessed and unloaded to the unloading cassette 621. Therefore, theproductivity is improved because an unmanned operation time is extended.

In addition, because the steps after the overcoat deposition to thelubricant-layer preparation are carried out without breaking vacuum, theincorporation or the adhesion of the contaminants with the overcoat andthe lubricant layer is prevented. Accordingly, the apparatus of thisembodiment can suppress the problems that: the recording layer may becontaminated; the adhesive strength of the lubricant layer may decrease;the thickness of the lubricant-layer may be made out of uniform; andcontrol accuracy of the bonded-ratio of lubricant-layer may decrease.Therefore, the apparatus of this embodiment is much suitable formanufacture of the magnetic recording disks, where the spacing isdecreasing.

In addition, because the contaminants on the substrate 9 are removed bythe plasma-enhanced ashing method and the gas blow method, the aboveadvantages are made higher. The plasma-enhanced ashing method iseffective mainly for removal of the organic contaminants. Thegas-blowing method is effective mainly for removal of the inorganiccontaminants such as metal or glass. After the cleanings in the firstcleaning chamber 22 and the second cleaning chamber 23, the substrate 9is transferred to the lubricant-layer preparation chamber 25 withoutbeing exposed to the atmosphere. The lubricant layer is prepared on thesurface of the substrate 9 that remains cleaned, because the surface isnot contaminated by the atmosphere. Therefore, the above advantages arealso made higher from this point.

In addition, because the burnishing is carried out in vacuum, thecontaminants in the atmosphere never adhere to the substrate 9 duringthe burnishing. From this point, the problems caused by the contaminantsare prevented as well. Because the substrate 9 is transferred to thepost-preparation treatment chamber 26 without being exposed to theatmosphere after the lubricant-layer deposition, this advantage is alsomade higher.

The point that the lubricant is used without diluting with solventbrings following advantages.

As solvent for the lubricant, flon (chloro-fluoro-carbon) conventionallyhas been used because the lubricant is fluoride. However, considering aproblem of the ozone layer destruction, use of flon-alternative solventsuch as perfluorocarbon has become a major issue. Still, even theflon-alternative solvent is sometimes questioned because that isregarded as a material causing the global warming.

Another problem with respect to the use of solvent is contamination ofthe lubricant layer. Diluted lubricant easily contains contaminants,resulting in that the contaminants are incorporated with the lubricantlayer. The contaminants in the lubricant layer may cause many kinds ofproblems that: the magnetic head is corroded by ionized contaminants;the magnetic head is mechanically damaged by the protrusions formed onthe surface of the lubricant layer; the magnetic head is chucked on thesurface of the magnetic recording disk because the lubricity decreases.Contrarily, the method and the apparatus of the embodiments are freefrom these problems because of no use of the solvent.

Nevertheless, a small amount of solvent is occasionally used on suchpurpose as to make it easier to deal with the lubricant. As solvent,perfluoroalkyl, for example, HFE7300 or HFE7100 of 3M Corporation may beused. A quantity of the solvent is one volume percentage or belowagainst the lubricant.

Next is described a magnetic disk manufacturing apparatus of the secondembodiment of the invention.

FIG. 15 shows a main part of the magnetic recording disk manufacturingapparatus of the second embodiment. The apparatus shown in FIG. 15 isdifferent from the described first embodiment in the composition of theplasma-enhanced ashing to clean the substrate 9. Concretely, in theembodiment shown in FIG. 15, the ashing is carried out in the overcoatdeposition chamber 15. FIG. 15 shows components on the overcoatdeposition chamber 15.

The components on the overcoat deposition chamber 15 are nearly the sameas those in FIG. 6, except the gas-introduction system 152. Thegas-introduction 152 shown in FIG. 15 can introduce a gas mixture ofcarbon hydride and hydrogen, or an oxygen gas selectively to theovercoat chamber 15.

In FIG. 15, when an overcoat is deposited, a gas mixture of hydrocarbonand hydrogen is introduced. After the overcoat deposition, withoutmoving the first substrate holder 51, the overcoat chamber 15 is pumpedby the pumping system down to about 5×10⁻² Pa. Then, the introduced gasis switched to oxygen by opening and closing the valves 154. The ashingis carried out by the oxygen plasma in the same way as the described.

The embodiment shown in FIG. 15 has an advantage that it is enabled toremove the contaminants not only on the substrate 9 but also on thefirst substrate holder 51. If the contaminants remain on the firstsubstrate holder 51, the contaminants may adhere to the next substrate 9held by the first substrate holder next. The apparatus of thisembodiment has an effect that the adhesion of the contaminants via thefirst substrate holder 51 is prevented in addition to the adhesiondirectly to the substrate 9. Moreover, it also possible to remove thecontaminants adhering to exposed surfaces of the components in theovercoat chamber 15.

Next is described a magnetic disk manufacturing apparatus of the thirdembodiment of the invention. FIG. 16 shows a main part of the magneticrecording disk manufacturing apparatus of the third embodiment of theinvention. The apparatus of the third embodiment has the feature thatthe third cleaning chamber 200 for cleaning the substrate 9 is added.The third cleaning chamber 200, for example, may be interposed betweenthe second cleaning chamber 23 and the burnishing chamber 24 in thelayout shown in FIG. 1. FIG. 16 shows a schematic side view of the thirdcleaning chamber 200.

In the third cleaning chamber 200 shown in FIG. 16, the substrate 9 iscleaned by laser irradiation. Concretely, the third cleaning chamber 200comprises a laser oscillator 201, and an introduction window 202 forintroducing laser beam into the chamber. The introduction window 202 ismounted airtightly shutting an opening formed on a wall of the thirdcleaning chamber 200.

The surface cleaning by laser irradiation is mainly conducted byablation. When the laser beam is irradiated on the contaminants adheringto the substrate 9, the contaminants are rapidly decomposed by energy ofthe laser beam. The third cleaning chamber 200 comprises a pumpingsystem 203 so that the laser irradiation cleaning can be carried out invacuum.

TABLE 2 shows an example of condition of the cleaning by laserirradiation.

TABLE 2 Preferred Condition of the Laser Irradiation Cleaning ConditionPreferred range or value Laser Excimer laser Wavelength 248 nmIrradiation energy density 200 mJ/cm² or below Irradiation type Pulse(1-100 Hz) The number of pulses 100 or below

If an irradiation energy density exceeds 200 mJ/cm2, there arises apossibility to erode the overcoat on the substrate 9. To carry out thecleaning without eroding the overcoat, a lower energy density, a lowerfrequency of the pulses or a smaller number of the pulses may beadopted. It is preferable to scan the laser beam in a radius directionof the substrate 9 while the substrate 9 is rotated so that the laserbeam can be irradiated uniformly on the whole surface of the substrate9. For this rotation, the same rotation mechanism as in the describedembodiment may be employed.

Next is described a magnetic disk manufacturing apparatus of the fourthembodiment of the invention. FIG. 17 shows a main part of the magneticrecording disk manufacturing apparatus of the fourth embodiment of theinvention. A point characterizing this embodiment is that the burnishingand the lubricant-layer preparation are carried out in the same chamber.In other words, a burnishing-preparation chamber 210 is provided insteadof the burnishing chamber 25 and the lubricant-layer preparation chamber26 in the first embodiment.

FIG. 17 shows a schematic side view of the burnishing-preparationchamber 210. The burnishing-preparation chamber 210 comprises a pumpingsystem 211 that discharges an air in the chamber, a rotation mechanism 8that holds and rotates the substrate 9 around the axis coaxial with thesubstrate 9, a burnishing tape that is pressed against the substrate 9being rotated by the rotation mechanism 8, and a lubricant coater 213that coats lubricant on the substrate 9 simultaneously with theburnishing by a burnishing tape 212.

Description about the rotation mechanism 8 and the burnishing tape 212are omitted because those are the same as in the described firstembodiment. The lubricant coater 213 is mainly composed of an ejector214 ejecting the lubricant from a tip thereof, a feeding tube 215connected with the ejector 214, and a pump (not shown) that feeds thelubricant from a lubricant storing vessel (not shown) to the ejector 214through the feeding tube 215. The lubricant coater 213 is provided ateach side of the substrate location.

An operation of the burnishing-preparation chamber 210 is described.

In a state that the burnishing-preparation chamber 210 is pumped toobtain a specific vacuum pressure, the second substrate holder 52holding the substrates 9 is moved into the burnishing-preparationchamber 210 and is stopped at a specific position. Then, the rotationmechanism 8 holds one of the substrates 9 and rotates it. During thisrotation, the pressure members 247 at both sides of the substrate 9 aredisplaced toward the substrate 9 by a drive source (not shown), therebypressing the burnishing tapes 212 against the substrate 9. As a result,the protrusions existing on the substrate 9 are removed.

Simultaneously, the lubricant coater 213 is operated. The lubricant isfed with the ejectors 214 by the pump through the feeding tubes 215. Thelubricant is ejected from the ejectors 214 and poured onto theburnishing tapes 212. The lubricant poured on the burnishing tapes 212is moved as the burnishing tapes 212 are moved. When the lubricantreaches a place where the burnishing tapes 212 are pressed against thesubstrate 9, the lubricant is thinly extended out between the burnishingtape 212 and the substrate 9. The extended lubricant adheres to thesubstrate 9. Thus, the lubricant is coated on the substrate 9.

The lubricant in this embodiment may be the same as in the describedembodiment, whose main component is PEPE. The use of a small amount ofthe solvent is allowed as described. A space pressure in theburnishing-preparation chamber 210 and a pressure strength by thepressure members 247 may be the same as those in the describedembodiment as well.

After the burnishing and the lubricant coating are simultaneouslycarried out on the whole surfaces of the substrate 9, the pressuremembers 247 are moved backward and the rotation by the rotationmechanism 8 is stopped. The second substrate holder 52 is moved to aposition where the rotation mechanism 8 can hold the other substrate 9.As the rotation mechanism 8 rotates the other substrate 9, theburnishing and the lubricant coating are simultaneously carried out onthe whole surfaces of the other substrate 9. Operations of thecomponents except the burnishing-preparation chamber 210 are the same asthose of the described first embodiment.

As understood from the above description, productivity in thisembodiment is enhanced because the burnishing and the lubricant-layerpreparation are simultaneously carried out in the burnishing-preparationchamber 210. Here, “simultaneously” includes the case that theburnishing and the lubricant-layer preparation are carried out literallyat the same time, and the case that the burnishing and thelubricant-layer preparation are carried out roughly at the same time,exactly not the same time. The apparatus of this embodiment also has anadvantage that the contaminants in the atmosphere cannot be incorporatedwith the lubricant layer because the burnishing and the lubricant-layerpreparation are carried out in vacuum. Therefore, the apparatuscontributes to manufacture of high-quality magnetic recording disks. Theadvantage that productivity is enhanced is still the same even whenthose are carried out in the atmosphere.

Carrying out the burnishing in vacuum and carrying out thelubricant-layer preparation in vacuum are closely related to each other.Though carrying out the burnishing in vacuum is much effective for thereduction of the contaminants, the burnishing possibly might beexcessive because a friction force between the burnishing tape 212 andthe substrate 9 is higher than that in the atmosphere. “Excessive” meansa situation that not only the protrusions are removed, but the depositedovercoat is also scraped off. Contrarily, the raw lubricant generallyhas a high viscosity. If the lubricant may be diluted with the solvent,the coating can be made easier. However, the use of the solvent bringsthe described problems.

This embodiment has an advantage of solving these conflicting problemsat once, that is, a ‘killing two birds with one stone’ solution. Whenthe lubricant is coated on the substrate 9 via the burnishing tape 212,the lubricant coating is made easier even if a viscosity of thelubricant is high, in addition to that the excessive burnishing isprevented by the lubricant inserted between the burnishing tape 212 andthe substrate 9.

Though the lubricant-layer preparation is carried out by pouring thelubricant on the burnishing tape 212 in this embodiment, the vapordeposition as in the first embodiment may be employed by providing pots252 and heaters 253 as shown in FIG. 13 in the burnishing-preparationchamber 210.

The lubricant-layer preparation also may be carried out by a sprayingmethod. Concretely, a sprayer is provided at each side of the substratelocation in the burnishing-preparation chamber 210. Lubricant dilutedwith solvent is sprayed from the sprayers onto the substrate 9.

Next is described a magnetic disk manufacturing apparatus of the fifthembodiment of the invention. FIG. 18 shows a main part of the magneticrecording disk manufacturing apparatus of the fifth embodiment of theinvention.

The fifth embodiment is different from the described first embodiment inthe components on the burnishing chamber 24. In the fifth embodiment, acleaning means 88 is provided. The cleaning means 88 cleans a surface ofthe burnishing tape 242 in vacuum prior to the burnishing.

A film containing oxygen ions or sulfuric ions, dusts, or organicsubstance such as fat and oil may adhere to the surface of theburnishing tape 242 as contaminants. If the burnishing is carried out ina state that such contaminants adhere to the surface of the burnishingtape 242, the contaminants may transfer to the substrate 9.

Considering this, the surface of the burnishing tape 242 is cleaned bythe cleaning means 88 prior to the burnishing in this embodiment.Concretely, the cleaning means 88 is mainly composed of an ion-beamsource 881 provided in the burnishing chamber 24, and a gas supplysystem 882 that supplies a material gas with the ion-beam source 881.

The gas supply system 882 supplies an argon gas or an oxygen gas. Theion-beam source 881 irradiates beam of argon ion or oxygen ion onto theburnishing tape 242. Acceleration energy of the ion beam is preferably250-600 eV. An incident angle of the ion beam onto to the burnishingtape 242 is preferably 30-40 degrees. If the burnishing tape 242 may bedamaged by the ion beam, the acceleration energy is made lower, or theincident angle is made smaller.

An irradiation pattern of the ion beam is a rectangle whose width is thesame as the burnishing tape 242 or slightly larger, and whose length isabout 30 mm. The ion-beam source 881 has a focusing electrode, whichfocuses the ion beam so that this irradiation pattern can be obtained.

The incident ion beam onto the burnishing tape 242 bombards or scrapesthe contaminants existing on the surface of the burnishing tape 242,thereby removing them. As a result, the surface of the burnishing tape242 is cleaned. The burnishing is carried out by pressing the cleanedsurface of the burnishing tape 242 onto the substrate 9. Therefore, thecontaminants are prevented from adhering to the substrate 9.

Though the surface of the burnishing tape 242 is cleaned by the ion beamin this embodiment, it is possible to clean it by plasma or laser. It isalso possible to clean the surface of the burnishing tape 242 using themethod in the fourth embodiment.

Next is described about an in-line type substrate processing apparatusof an embodiment of the invention. The magnetic-recording diskmanufacturing apparatus shown in FIG. 1 is concurrently an in-line typesubstrate processing apparatus. The apparatus comprises a plurality ofvacuum chambers 10-17, 20-29 connected along two circumventive transferpaths 1, 2, and the shifting robot 63 that transfers the substrate 9 invacuum without exposing the substrate 9 to the atmosphere along thethird transfer path 3 that interconnects the first path 1 and the secondpath 2.

The described structure is a kind of circumventive in-line typeapparatus. U.S. Pat. No. 5,846,328 discloses the same kind of apparatus.This type of apparatus has a merit that the substrate holder does notbring contaminants in the atmosphere into the apparatus because thesubstrate holder is not taken out to the atmosphere. However, if it isintended to provide more vacuum chambers in such a kind of in-line typeapparatus, a transfer path with a longer length is required. As imaginedfrom FIG. 1, if the transfer path is longer, a space surrounded by thetransfer path is larger. This space is not essential for the substrateprocessing. If whole occupation space of the apparatus increases with anincrease in such a non-essential space, it is not a preferable result.

Contrarily, by providing additional vacuum chambers along anothercircumventive transfer path as in the apparatus of this embodiment, thenumber of vacuum chambers can be increased without much increase in thewhole occupation space of the apparatus. Therefore, this solution isvery much suitable for the case that a larger number of processes areintended to carry out without breaking vacuum.

An application of the idea of such an in-line type substrate processingapparatus is not limited to the described manufacture of magneticrecording disks. For example, the idea can be applied to manufacture ofoptical information recording media such as a compact disc, andmanufacture of display devices such as a liquid crystal display, as faras the in-line type apparatus is used.

The circumventive transfer path may have another shape than a rectangle.For example, the circumventive transfer path may have a shape of atriangle, a circle, a pentagon, or the like. This invention is notlimited to the use of the substrate holder that holds two substratessimultaneously. It is possible to employ a substrate holder that holdsonly one substrate, or holds three or more substrates simultaneously.

The magnetic-recording disk manufacturing apparatus of the invention isnot limited to the described in-line type. For example, the inventionincludes a cluster-tool type apparatus where process chambers, a loadlock chamber and an unload lock chamber are provided around a transferchamber in which a transfer robot is provided.

The term “magnetic-recording disk manufacturing apparatus” generallymeans an apparatus for manufacturing a magnetic recording disk.Therefore, it includes an apparatus with which all processes formanufacturing a magnetic recording disk are carried out, and anapparatus with which not all processes are carried out.

The term “magnetic recording disk” means a disk where information isrecorded utilizing an effect of magnetism in general. Therefore, itincludes a disk utilizing another effect than magnetism in addition tothe magnetism, such as a magneto-optical recording disk.

1-19. (canceled)
 20. A method for manufacturing a magnetic recordingdisk, comprising depositing a magnetic film on a substrate for arecording layer in a magnetic-film deposition chamber; carrying out aburnishing and a lubricant-layer preparation in a burnishing-preparationchamber after depositing the magnetic film, the burnishing being a stepwhere protrusions on the substrate are removed by rubbing the substratewith a burnishing tape, the lubricant-layer preparation being a stepwhere a lubricant layer is prepared on the substrate; pouring thelubricant on the burnishing tape to be rubbed with, thereby providingthe lubricant between the burnishing tape and the substrate during theburnishing to ease friction force therebetween; evacuating theburnishing-preparation chamber at 10⁻² to 100 Pa while the burnishingand the lubricant layer preparation are carried out; and pressing theburnishing tape onto the substrate at 9.8 to 588 mN during theburnishing.
 21. A method for manufacturing a magnetic recording disk asclaimed in claim 20, further comprising transferring the substrate fromthe deposition chamber to the burnishing-preparation chamber withoutexposing the substrate to atmosphere.
 22. A method for manufacturing amagnetic recording disk as claimed in claim 20, wherein the lubricant isnot diluted with solvent.
 23. A method for manufacturing a magneticrecording disk as claimed in claim 20, wherein the substrate isdisk-shaped, further comprising transferring the substrate from thedeposition chamber to the burnishing-preparation chamber withoutexposing the substrate to atmosphere through a gate valve provided at aboundary of the deposition chamber and the burnishing-preparationchamber.
 24. A method for manufacturing a magnetic recording disk,comprising depositing magnetic films on both sides of a substrate forrecording layers in a magnetic-film deposition chamber; carrying out aburnishing and a lubricant-layer preparation in a burnishing-preparationchamber after depositing the magnetic films, the burnishing being a stepwhere protrusions on the substrate are removed by rubbing the both sidesof the substrate with burnishing tapes, the lubricant-layer preparationbeing a step where lubricant layers is prepared on the both sides of thesubstrate; pouring the lubricant on the burnishing tapes to be rubbedwith, thereby providing the lubricant between the burnishing tapes andthe substrate during the burnishing to ease friction force therebetween;evacuating the burnishing-preparation chamber at 10⁻² to 100 Pa whilethe burnishing and the lubricant layer preparation are carried out; andpressing the burnishing tapes onto the substrate at 9.8 to 588 mN duringthe burnishing.
 25. A method for manufacturing a magnetic recording diskas claimed in claim 20, further comprising removing contaminantsexisting on a surface of the burnishing tape in vacuum prior to theburnishing.
 26. A method for manufacturing a magnetic recording disk asclaimed in claim 25, further comprising irradiating the burnishing tapewith an ion beam to bombard and scrape the contaminants thereon.
 27. Amethod for manufacturing a magnetic recording disk as claimed in claim26, wherein an incident angle of the ion beam onto the burnishing tapeis in a range of 40-50 degrees.
 28. A method for manufacturing amagnetic recording disk as claimed in claim 26, wherein ion-beamacceleration energy of the ion-beam source is in a range of 250-600 eV.29. A method for manufacturing a magnetic recording disk as claimed inclaim 20, further comprising carrying out a post-preparation treatmentin vacuum after the burnishing and the preparation, the post-preparationtreatment being a step to coordinate adhesive strength and surfacelubricity of the lubricant layer by heating or irradiating the lubricantlayer.
 30. An method for manufacturing a magnetic recording disk asclaimed in claim 29, wherein the post-preparation treatment is carriedout in a post-preparation chamber without exposing the substrate toatmosphere.